bird/proto/ospf/topology.c

/*
 *	BIRD -- OSPF Topological Database
 *
 *	(c) 1999       Martin Mares <mj@ucw.cz>
 *	(c) 1999--2004 Ondrej Filip <feela@network.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#include "nest/bird.h"
#include "lib/string.h"

#include "ospf.h"

#define HASH_DEF_ORDER 6
#define HASH_HI_MARK *4
#define HASH_HI_STEP 2
#define HASH_HI_MAX 16
#define HASH_LO_MARK /5
#define HASH_LO_STEP 2
#define HASH_LO_MIN 8

void originate_prefix_rt_lsa(struct ospf_area *oa);
void originate_prefix_net_lsa(struct ospf_iface *ifa);
void flush_prefix_net_lsa(struct ospf_iface *ifa);

#ifdef OSPFv2
#define ipa_to_rid(x) _I(x)
#else /* OSPFv3 */
#define ipa_to_rid(x) _I3(x)
#endif

/* FIXME very ugly hack */
#ifdef OSPFv2
#define ipa_to_lsaid(x) _I(x)
#else /* OSPFv3 */
#define ipa_to_lsaid(x) _I0(x) ^ _I1(x) ^ _I2(x) ^ _I3(x)
#endif


static void *
lsab_alloc(struct proto_ospf *po, unsigned size)
{
  unsigned offset = po->lsab_used;
  po->lsab_used += size;
  if (po->lsab_used > po->lsab_size)
    {
      po->lsab_size = MAX(po->lsab_used, 2 * po->lsab_size);
      po->lsab = mb_realloc(po->proto.pool, po->lsab, po->lsab_size);
    }
  return ((byte *) po->lsab) + offset;
}

static inline void *
lsab_allocz(struct proto_ospf *po, unsigned size)
{
  void *r = lsab_alloc(po, size);
  bzero(r, size);
  return r;
}

static inline void *
lsab_flush(struct proto_ospf *po)
{
  void *r = mb_alloc(po->proto.pool, po->lsab_size);
  memcpy(r, po->lsab, po->lsab_used);
  po->lsab_used = 0;
  return r;
}

static inline void *
lsab_offset(struct proto_ospf *po, unsigned offset)
{
  return ((byte *) po->lsab) + offset;
}

static inline void *
lsab_end(struct proto_ospf *po)
{
  return ((byte *) po->lsab) + po->lsab_used;
}

#ifdef OSPFv3

#define IPV6_PREFIX_SPACE(x) ((((x) + 63) / 32) * 4)
#define IPV6_PREFIX_WORDS(x) (((x) + 63) / 32)

static inline u32 *
put_ipv6_prefix(u32 *buf, ip_addr addr, u8 pxlen, u8 pxopts, u16 lh)
{
  *buf++ = ((pxlen << 24) | (pxopts << 16) | lh);

  if (pxlen > 0)
    *buf++ = _I0(addr);
  if (pxlen > 32)
    *buf++ = _I1(addr);
  if (pxlen > 64)
    *buf++ = _I2(addr);
  if (pxlen > 96)
    *buf++ = _I3(addr);
  return buf;
}


static inline u32 *
put_ipv6_addr(u32 *buf, ip_addr addr)
{
  *(ip_addr *) buf = addr;
  return buf + 4;
}

#endif


static int
configured_stubnet(struct ospf_area *oa, struct ifa *a)
{
  struct ospf_stubnet_config *sn;
  WALK_LIST(sn, oa->ac->stubnet_list)
    {
      if (sn->summary)
	{
	  if (ipa_in_net(a->prefix, sn->px.addr, sn->px.len) && (a->pxlen >= sn->px.len))
	    return 1;
	}
      else
	{
	  if (ipa_equal(a->prefix, sn->px.addr) && (a->pxlen == sn->px.len))
	    return 1;
	}
    }
  return 0;
}

int
bcast_net_active(struct ospf_iface *ifa)
{
  struct ospf_neighbor *neigh;

  if (ifa->state == OSPF_IS_WAITING)
    return 0;

  WALK_LIST(neigh, ifa->neigh_list)
    {
      if (neigh->state == NEIGHBOR_FULL)
	{
	  if (neigh->rid == ifa->drid)
	    return 1;

	  if (ifa->state == OSPF_IS_DR)
	    return 1;
	}
    }

  return 0;
}


#ifdef OSPFv2

static void *
originate_rt_lsa_body(struct ospf_area *oa, u16 *length)
{
  struct proto_ospf *po = oa->po;
  struct ospf_iface *ifa;
  int i = 0, bitv = 0;
  struct ospf_lsa_rt *rt;
  struct ospf_lsa_rt_link *ln;
  struct ospf_neighbor *neigh;

  DBG("%s: Originating RT_lsa body for area %R.\n", po->proto.name,
      oa->areaid);
    
  ASSERT(po->lsab_used == 0);
  rt = lsab_allocz(po, sizeof(struct ospf_lsa_rt));

  rt->options = 0;

  if (po->areano > 1)
    rt->options |= OPT_RT_B;

  if ((po->ebit) && (!oa->stub))
    rt->options |= OPT_RT_E;

  rt = NULL; /* buffer might be reallocated later */

  WALK_LIST(ifa, po->iface_list)
  {
    int master = 0;

    if ((ifa->type == OSPF_IT_VLINK) && (ifa->voa == oa) &&
	(!EMPTY_LIST(ifa->neigh_list)))
    {
      neigh = (struct ospf_neighbor *) HEAD(ifa->neigh_list);
      if ((neigh->state == NEIGHBOR_FULL) && (ifa->cost <= 0xffff))
	bitv = 1;
    }

    if ((ifa->oa != oa) || (ifa->state == OSPF_IS_DOWN))
      continue;

    /* BIRD does not support interface loops */
    ASSERT(ifa->state != OSPF_IS_LOOP);

    switch (ifa->type)
      {
      case OSPF_IT_PTP:	/* RFC2328 - 12.4.1.1 */
	neigh = (struct ospf_neighbor *) HEAD(ifa->neigh_list);
	if ((!EMPTY_LIST(ifa->neigh_list)) && (neigh->state == NEIGHBOR_FULL))
	{
	  ln = lsab_alloc(po, sizeof(struct ospf_lsa_rt_link));
	  ln->type = LSART_PTP;
	  ln->id = neigh->rid;
	  ln->data = (ifa->iface->addr->flags & IA_UNNUMBERED) ?
	    ifa->iface->index : ipa_to_u32(ifa->iface->addr->ip);
	  ln->metric = ifa->cost;
	  ln->notos = 0;
	  i++;
	  master = 1;
	}
	break;

      case OSPF_IT_BCAST: /* RFC2328 - 12.4.1.2 */
      case OSPF_IT_NBMA:
	if (bcast_net_active(ifa))
	  {
	    ln = lsab_alloc(po, sizeof(struct ospf_lsa_rt_link));
	    ln->type = LSART_NET;
	    ln->id = ipa_to_u32(ifa->drip);
	    ln->data = ipa_to_u32(ifa->iface->addr->ip);
	    ln->metric = ifa->cost;
	    ln->notos = 0;
	    i++;
	    master = 1;
	  }
	break;

      case OSPF_IT_VLINK: /* RFC2328 - 12.4.1.3 */
	neigh = (struct ospf_neighbor *) HEAD(ifa->neigh_list);
	if ((!EMPTY_LIST(ifa->neigh_list)) && (neigh->state == NEIGHBOR_FULL) && (ifa->cost <= 0xffff))
	{
	  ln = lsab_alloc(po, sizeof(struct ospf_lsa_rt_link));
	  ln->type = LSART_VLNK;
	  ln->id = neigh->rid;
	  ln->data = ipa_to_u32(ifa->iface->addr->ip);
	  ln->metric = ifa->cost;
	  ln->notos = 0;
	  i++;
	  master = 1;
        }
        break;

      default:
        log("Unknown interface type %s", ifa->iface->name);
        break;
      }

    /* Now we will originate stub areas for interfaces addresses */
    struct ifa *a;
    WALK_LIST(a, ifa->iface->addrs)
      {
	if (((a == ifa->iface->addr) && master) ||
	    (a->flags & IA_SECONDARY) ||
	    (a->flags & IA_UNNUMBERED) ||
	    configured_stubnet(oa, a))
	  continue;


	ln = lsab_alloc(po, sizeof(struct ospf_lsa_rt_link));
	ln->type = LSART_STUB;
	ln->id = ipa_to_u32(a->prefix);
	ln->data = ipa_to_u32(ipa_mkmask(a->pxlen));
	ln->metric = ifa->cost;
	ln->notos = 0;
	i++;
      }
  }

  struct ospf_stubnet_config *sn;
  WALK_LIST(sn, oa->ac->stubnet_list)
    if (!sn->hidden)
      {
	ln = lsab_alloc(po, sizeof(struct ospf_lsa_rt_link));
	ln->type = LSART_STUB;
	ln->id = ipa_to_u32(sn->px.addr);
	ln->data = ipa_to_u32(ipa_mkmask(sn->px.len));
	ln->metric = sn->cost;
	ln->notos = 0;
	i++;
      }

  rt = po->lsab;
  rt->links = i;

  if (bitv) 
    rt->options |= OPT_RT_V;

  *length = po->lsab_used + sizeof(struct ospf_lsa_header);
  return lsab_flush(po);
}

#else /* OSPFv3 */

static void
add_lsa_rt_link(struct proto_ospf *po, struct ospf_iface *ifa, u8 type, u32 nif, u32 id)
{
  struct ospf_lsa_rt_link *ln = lsab_alloc(po, sizeof(struct ospf_lsa_rt_link));
  ln->type = type;
  ln->padding = 0;
  ln->metric = ifa->cost;
  ln->lif = ifa->iface->index;
  ln->nif = nif;
  ln->id = id;
}

static void *
originate_rt_lsa_body(struct ospf_area *oa, u16 *length)
{
  struct proto_ospf *po = oa->po;
  struct ospf_iface *ifa;
  int bitv = 0;
  struct ospf_lsa_rt *rt;
  struct ospf_neighbor *neigh;

  DBG("%s: Originating RT_lsa body for area %R.\n", po->proto.name,
      oa->areaid);
  
  ASSERT(po->lsab_used == 0);
  rt = lsab_allocz(po, sizeof(struct ospf_lsa_rt));

  rt->options = oa->options & OPTIONS_MASK;

  if (po->areano > 1)
    rt->options |= OPT_RT_B;

  if ((po->ebit) && (!oa->stub))
    rt->options |= OPT_RT_E;

  rt = NULL; /* buffer might be reallocated later */

  WALK_LIST(ifa, po->iface_list)
  {
    if ((ifa->type == OSPF_IT_VLINK) && (ifa->voa == oa) &&
	(!EMPTY_LIST(ifa->neigh_list)))
    {
      neigh = (struct ospf_neighbor *) HEAD(ifa->neigh_list);
      if ((neigh->state == NEIGHBOR_FULL) && (ifa->cost <= 0xffff))
	bitv = 1;
    }

    if ((ifa->oa != oa) || (ifa->state == OSPF_IS_DOWN))
      continue;

    /* BIRD does not support interface loops */
    ASSERT(ifa->state != OSPF_IS_LOOP);

    /* RFC5340 - 4.4.3.2 */
    switch (ifa->type)
      {
      case OSPF_IT_PTP:
	neigh = (struct ospf_neighbor *) HEAD(ifa->neigh_list);
	if ((!EMPTY_LIST(ifa->neigh_list)) && (neigh->state == NEIGHBOR_FULL))
	  add_lsa_rt_link(po, ifa, LSART_PTP, neigh->iface_id, neigh->rid);
	break;

      case OSPF_IT_BCAST:
      case OSPF_IT_NBMA:
	if (bcast_net_active(ifa))
	  add_lsa_rt_link(po, ifa, LSART_NET, ifa->dr_iface_id, ifa->drid);
	break;

      case OSPF_IT_VLINK:
	neigh = (struct ospf_neighbor *) HEAD(ifa->neigh_list);
	if ((!EMPTY_LIST(ifa->neigh_list)) && (neigh->state == NEIGHBOR_FULL) && (ifa->cost <= 0xffff))
	  add_lsa_rt_link(po, ifa, LSART_VLNK, neigh->iface_id, neigh->rid);
        break;

      default:
        log("Unknown interface type %s", ifa->iface->name);
        break;
      }
  }

  if (bitv)
    {
      rt = po->lsab;
      rt->options |= OPT_RT_V;
    }

  *length = po->lsab_used + sizeof(struct ospf_lsa_header);
  return lsab_flush(po);
}

#endif

/**
 * originate_rt_lsa - build new instance of router LSA
 * @oa: ospf_area which is LSA built to
 *
 * It builds router LSA walking through all OSPF interfaces in
 * specified OSPF area. This function is mostly called from
 * area_disp(). Builds new LSA, increases sequence number (if old
 * instance exists) and sets age of LSA to zero.
 */
void
originate_rt_lsa(struct ospf_area *oa)
{
  struct ospf_lsa_header lsa;
  struct proto_ospf *po = oa->po;
  struct proto *p = &po->proto;
  u32 rid = po->proto.cf->global->router_id;
  void *body;

  OSPF_TRACE(D_EVENTS, "Originating RT_lsa for area %R.", oa->areaid);

  lsa.age = 0;
  lsa.type = LSA_T_RT;
  
#ifdef OSPFv2
  lsa.options = oa->options;
#endif
  
  lsa.id = rid;
  lsa.rt = rid;
  lsa.sn = oa->rt ? (oa->rt->lsa.sn + 1) : LSA_INITSEQNO;
  u32 dom = oa->areaid;

  body = originate_rt_lsa_body(oa, &lsa.length);
  lsasum_calculate(&lsa, body);
  oa->rt = lsa_install_new(po, &lsa, dom, body);
  ospf_lsupd_flood(po, NULL, NULL, &lsa, dom, 1);
}

void
update_rt_lsa(struct ospf_area *oa)
{
  struct proto_ospf *po = oa->po;

  if ((oa->rt) && ((oa->rt->inst_t + MINLSINTERVAL)) > now)
    return;
  /*
   * Tick is probably set to very low value. We cannot
   * originate new LSA before MINLSINTERVAL. We will
   * try to do it next tick.
   */

  originate_rt_lsa(oa);
#ifdef OSPFv3
  originate_prefix_rt_lsa(oa);
#endif

  schedule_rtcalc(po);
  oa->origrt = 0;
}

static void *
originate_net_lsa_body(struct ospf_iface *ifa, u16 *length,
		       struct proto_ospf *po)
{
  u16 i = 1;
  struct ospf_neighbor *n;
  struct ospf_lsa_net *net;
  int nodes = ifa->fadj + 1;

  net = mb_alloc(po->proto.pool, sizeof(struct ospf_lsa_net)
		 + nodes * sizeof(u32));

#ifdef OSPFv2
  net->netmask = ipa_mkmask(ifa->iface->addr->pxlen);
#endif

#ifdef OSPFv3
  /* In OSPFv3, we would like to merge options from Link LSAs of added neighbors */
  struct top_hash_entry *en;
  u32 options = 0;
#endif

  net->routers[0] = po->proto.cf->global->router_id;

  WALK_LIST(n, ifa->neigh_list)
  {
    if (n->state == NEIGHBOR_FULL)
    {
#ifdef OSPFv3
      en = ospf_hash_find(po->gr, ifa->iface->index, n->iface_id, n->rid, LSA_T_LINK);
      if (en)
	options |= ((struct ospf_lsa_link *) en->lsa_body)->options;
#endif

      net->routers[i] = n->rid;
      i++;
    }
  }
  ASSERT(i == nodes);

#ifdef OSPFv3
  net->options = options & OPTIONS_MASK;
#endif
  
  *length = sizeof(struct ospf_lsa_header) + sizeof(struct ospf_lsa_net)
    + nodes * sizeof(u32);
  return net;
}


/**
 * originate_net_lsa - originates of deletes network LSA
 * @ifa: interface which is LSA originated for
 *
 * Interface counts number of adjacent neighbors. If this number is
 * lower than one or interface is not in state %OSPF_IS_DR it deletes
 * and premature ages instance of network LSA for specified interface.
 * In other case, new instance of network LSA is originated.
 */
void
originate_net_lsa(struct ospf_iface *ifa)
{
  struct proto_ospf *po = ifa->oa->po;
  struct ospf_lsa_header lsa;
  u32 rid = po->proto.cf->global->router_id;
  u32 dom = ifa->oa->areaid;
  struct proto *p = &po->proto;
  void *body;

  OSPF_TRACE(D_EVENTS, "Originating Net lsa for iface \"%s\".",
	     ifa->iface->name);

  lsa.age = 0;
  lsa.type = LSA_T_NET;

#ifdef OSPFv2
  lsa.options = ifa->oa->options;
  lsa.id = ipa_to_u32(ifa->iface->addr->ip);
#else /* OSPFv3 */
  lsa.id = ifa->iface->index;
#endif

  lsa.rt = rid;
  lsa.sn = ifa->net_lsa ? (ifa->net_lsa->lsa.sn + 1) : LSA_INITSEQNO;

  body = originate_net_lsa_body(ifa, &lsa.length, po);
  lsasum_calculate(&lsa, body);
  ifa->net_lsa = lsa_install_new(po, &lsa, dom, body);
  ospf_lsupd_flood(po, NULL, NULL, &lsa, dom, 1);
}

void
flush_net_lsa(struct ospf_iface *ifa)
{
  struct proto_ospf *po = ifa->oa->po;
  struct proto *p = &po->proto;
  u32 dom = ifa->oa->areaid;

  if (ifa->net_lsa == NULL)
    return;

  OSPF_TRACE(D_EVENTS, "Deleting Net lsa for iface \"%s\".",
	     ifa->iface->name);
  ifa->net_lsa->lsa.sn += 1;
  ifa->net_lsa->lsa.age = LSA_MAXAGE;
  lsasum_calculate(&ifa->net_lsa->lsa, ifa->net_lsa->lsa_body);
  ospf_lsupd_flood(po, NULL, NULL, &ifa->net_lsa->lsa, dom, 0);
  flush_lsa(ifa->net_lsa, po);
  ifa->net_lsa = NULL;
}

void
update_net_lsa(struct ospf_iface *ifa)
{
  struct proto_ospf *po = ifa->oa->po;
 
  if (ifa->net_lsa && ((ifa->net_lsa->inst_t + MINLSINTERVAL) > now))
    return;
  /*
   * It's too early to originate new network LSA. We will
   * try to do it next tick
   */

  if ((ifa->state != OSPF_IS_DR) || (ifa->fadj == 0))
    {
      flush_net_lsa(ifa);
#ifdef OSPFv3
      flush_prefix_net_lsa(ifa);
#endif
    }
  else
    {
      originate_net_lsa(ifa);
#ifdef OSPFv3
      originate_prefix_net_lsa(ifa);
#endif
    }

  schedule_rtcalc(po);
  ifa->orignet = 0;
}

#ifdef OSPFv2

static void *
originate_sum_lsa_body(struct proto_ospf *po, u16 *length, u32 mlen, u32 metric)
{
  struct ospf_lsa_sum *sum = mb_alloc(po->proto.pool, sizeof(struct ospf_lsa_sum));
  *length = sizeof(struct ospf_lsa_header) + sizeof(struct ospf_lsa_sum);

  sum->netmask = ipa_mkmask(mlen);
  sum->metric = metric;

  return sum;
}

#define originate_sum_net_lsa_body(po,length,fn,metric) \
  originate_sum_lsa_body(po, length, (fn)->pxlen, metric)

#define originate_sum_rt_lsa_body(po,length,drid,metric,options) \
  originate_sum_lsa_body(po, length, 0, metric)

#else /* OSPFv3 */

static void *
originate_sum_net_lsa_body(struct proto_ospf *po, u16 *length, struct fib_node *fn, u32 metric)
{
  int size = sizeof(struct ospf_lsa_sum_net) + IPV6_PREFIX_SPACE(fn->pxlen);
  struct ospf_lsa_sum_net *sum = mb_alloc(po->proto.pool, size);
  *length = sizeof(struct ospf_lsa_header) + size;

  sum->metric = metric;
  put_ipv6_prefix(sum->prefix, fn->prefix, fn->pxlen, 0, 0);

  return sum;
}

static void *
originate_sum_rt_lsa_body(struct proto_ospf *po, u16 *length, u32 drid, u32 metric, u32 options)
{
  struct ospf_lsa_sum_rt *sum = mb_alloc(po->proto.pool, sizeof(struct ospf_lsa_sum_rt));
  *length = sizeof(struct ospf_lsa_header) + sizeof(struct ospf_lsa_sum_rt);

  sum->options = options & OPTIONS_MASK;
  sum->metric = metric;
  sum->drid = drid;

  return sum;
}

#endif

void
originate_sum_lsa(struct ospf_area *oa, struct fib_node *fn, int type, int metric, u32 options)
{
  struct proto_ospf *po = oa->po;
  struct proto *p = &po->proto;
  struct top_hash_entry *en;
  u32 rid = po->proto.cf->global->router_id;
  struct ospf_lsa_header lsa;
  void *body;

  /* options argument is used in ORT_NET and OSPFv3 only */

  lsa.age = 0;
  lsa.rt = rid;
  lsa.sn = LSA_INITSEQNO;
#ifdef OSPFv2
  lsa.options = oa->options;
#endif

  if (type == ORT_NET)
    {
      /* FIXME proper handling of LSA IDs and check for the same network */
      lsa.id = ipa_to_lsaid(fn->prefix);
      lsa.type = LSA_T_SUM_NET;
    }
  else
    {
      /* In OSPFv6, LSA ID is meaningless, but we still use Router ID of ASBR */
      lsa.id = ipa_to_rid(fn->prefix);
      lsa.type = LSA_T_SUM_RT;
    }

  u32 dom = oa->areaid;  

  /* FIXME check for the same LSA */
  if ((en = ospf_hash_find_header(po->gr, oa->areaid, &lsa)) != NULL)
    lsa.sn = en->lsa.sn + 1;

  if (type == ORT_NET)
    {
      OSPF_TRACE(D_EVENTS, "Originating Net-Summary-LSA for %I/%d (metric %d).",
		 fn->prefix, fn->pxlen, metric);

      body = originate_sum_net_lsa_body(po, &lsa.length, fn, metric);
    }
  else
    {
      OSPF_TRACE(D_EVENTS, "Originating RT-Summary-LSA for %R (metric %d).",
		 lsa.id, metric);

      body = originate_sum_rt_lsa_body(po, &lsa.length, lsa.id, metric, options);
    }

  lsasum_calculate(&lsa, body);
  en = lsa_install_new(po, &lsa, dom, body);
  ospf_lsupd_flood(po, NULL, NULL, &lsa, dom, 1);
}


void
flush_sum_lsa(struct ospf_area *oa, struct fib_node *fn, int type)
{
  struct proto_ospf *po = oa->po;
  struct proto *p = &po->proto;
  struct top_hash_entry *en;
  u32 rid = po->proto.cf->global->router_id;
  struct ospf_lsa_header lsa;

  lsa.rt = rid;
  if (type == ORT_NET)
    {
      /* FIXME proper handling of LSA IDs and check for the same network */
      lsa.id = ipa_to_lsaid(fn->prefix);
      lsa.type = LSA_T_SUM_NET;
    }
  else
    {
      /* In OSPFv6, LSA ID is meaningless, but we still use Router ID of ASBR */
      lsa.id = ipa_to_rid(fn->prefix);
      lsa.type = LSA_T_SUM_RT;
    }

  if ((en = ospf_hash_find_header(po->gr, oa->areaid, &lsa)) != NULL)
    {
      struct ospf_lsa_sum *sum = en->lsa_body;
      en->lsa.age = LSA_MAXAGE;
      en->lsa.sn = LSA_MAXSEQNO;
      lsasum_calculate(&en->lsa, sum);

      OSPF_TRACE(D_EVENTS, "Flushing summary lsa. (id=%R, type=%d)",
		 en->lsa.id, en->lsa.type);
      ospf_lsupd_flood(po, NULL, NULL, &en->lsa, oa->areaid, 1);
      if (can_flush_lsa(po)) flush_lsa(en, po);
    }
}


void
check_sum_lsa(struct proto_ospf *po, ort *nf, int dest)
{
  struct ospf_area *oa;
  int flush, mlen;
  ip_addr ip;

  if (po->areano < 2) return;

  if ((nf->n.type > RTS_OSPF_IA) && (nf->o.type > RTS_OSPF_IA)) return;

#ifdef LOCAL_DEBUG
  DBG("Checking...dest = %d, %I/%d\n", dest, nf->fn.prefix, nf->fn.pxlen);
  if (nf->n.oa) DBG("New: met=%d, oa=%d\n", nf->n.metric1, nf->n.oa->areaid);
  if (nf->o.oa) DBG("Old: met=%d, oa=%d\n", nf->o.metric1, nf->o.oa->areaid);
#endif

  WALK_LIST(oa, po->area_list)
  {
    flush = 0;
    if ((nf->n.metric1 >= LSINFINITY) || (nf->n.type > RTS_OSPF_IA))
      flush = 1;
    if ((dest == ORT_ROUTER) && (!(nf->n.options & ORTA_ASBR)))
      flush = 1;
    if ((!nf->n.oa) || (nf->n.oa->areaid == oa->areaid))
      flush = 1;

    if (nf->n.ifa) {
      if (nf->n.ifa->oa->areaid == oa->areaid)
        flush = 1;
      }
    else flush = 1;

    /* Don't send summary into stub areas
     * We send just default route (and later) */
    if (oa->stub)
      flush = 1;
    
    mlen = nf->fn.pxlen;
    ip = ipa_and(nf->fn.prefix, ipa_mkmask(mlen));

    if ((oa == po->backbone) && (nf->n.type == RTS_OSPF_IA))
      flush = 1;	/* Only intra-area can go to the backbone */

    if ((!flush) && (dest == ORT_NET) && fib_route(&nf->n.oa->net_fib, ip, mlen))
    {
      /* The route fits into area networks */
      flush = 1;
      if ((nf->n.oa == po->backbone) && (oa->trcap)) flush = 0;
    }

    if (flush)
      flush_sum_lsa(oa, &nf->fn, dest);
    else
      originate_sum_lsa(oa, &nf->fn, dest, nf->n.metric1, nf->n.options);
  }
}


static void *
originate_ext_lsa_body(net *n, rte *e, u16 *length, struct proto_ospf *po,
		       struct ea_list *attrs)
{
  struct proto *p = &po->proto;
  struct ospf_lsa_ext *ext;
  u32 m1 = ea_get_int(attrs, EA_OSPF_METRIC1, LSINFINITY);
  u32 m2 = ea_get_int(attrs, EA_OSPF_METRIC2, 10000);
  u32 tag = ea_get_int(attrs, EA_OSPF_TAG, 0);
  int gw = 0;
  int size = sizeof(struct ospf_lsa_ext);
  u32 *buf;

  if (!ipa_equal(e->attrs->gw, IPA_NONE))
  {
    /* FIXME: check for link-local in OSPFv3 ? */
    if (ospf_iface_find((struct proto_ospf *) p, e->attrs->iface) != NULL)
      gw = 1;
  }

#ifdef OSPFv3
  size += IPV6_PREFIX_SPACE(n->n.pxlen);

  if (gw)
    size += 16;
  
  if (tag)
    size += 4;
#endif
  
  ext = mb_alloc(p->pool, size);
  *length = sizeof(struct ospf_lsa_header) + size;

  ext->metric = (m1 != LSINFINITY) ? m1 : (m2 & LSA_EXT_EBIT); 

#ifdef OSPFv2
  ext->netmask = ipa_mkmask(n->n.pxlen);
  ext->fwaddr = gw ? IPA_NONE : e->attrs->gw;
  ext->tag = tag;
#else /* OSPFv3 */
  buf = ext->rest;
  buf = put_ipv6_prefix(buf, n->n.prefix, n->n.pxlen, 0, 0);

  if (gw)
    {
      ext->metric |= LSA_EXT_FBIT;
      buf = put_ipv6_addr(buf, e->attrs->gw);
    }

  if (tag)
    {
      ext->metric |= LSA_EXT_TBIT;
      *buf++ = tag;
    }
#endif

  return ext;
}

/**
 * originate_ext_lsa - new route received from nest and filters
 * @n: network prefix and mask
 * @e: rte
 * @po: current instance of OSPF
 * @attrs: list of extended attributes
 *
 * If I receive a message that new route is installed, I try to originate an
 * external LSA. The LSA header of such LSA does not contain information about
 * prefix length, so if I have to originate multiple LSAs for route with
 * different prefixes I try to increment prefix id to find a "free" one.
 *
 * The function also sets flag ebit. If it's the first time, the new router lsa
 * origination is necessary.
 */
void
originate_ext_lsa(net * n, rte * e, struct proto_ospf *po,
		  struct ea_list *attrs)
{
  struct ospf_lsa_header lsa;
  u32 rid = po->proto.cf->global->router_id;
  struct top_hash_entry *en = NULL;
  void *body;
  struct proto *p = &po->proto;
  struct ospf_area *oa;

  OSPF_TRACE(D_EVENTS, "Originating Ext lsa for %I/%d.", n->n.prefix,
	     n->n.pxlen);

  lsa.age = 0;
  lsa.type = LSA_T_EXT;
  lsa.rt = rid;
  lsa.sn = LSA_INITSEQNO;
#ifdef OSPFv2
  lsa.options = 0; /* or oa->options ? */
#endif

  /* FIXME proper handling of LSA IDs and check for the same network */
  lsa.id = ipa_to_lsaid(n->n.prefix);

  if ((en = ospf_hash_find_header(po->gr, 0, &lsa)) != NULL)
    {
      lsa.sn = en->lsa.sn + 1;
    }

  body = originate_ext_lsa_body(n, e, &lsa.length, po, attrs);
  lsasum_calculate(&lsa, body);

  en = lsa_install_new(po, &lsa, 0, body);
  ospf_lsupd_flood(po, NULL, NULL, &lsa, 0, 1);

  if (po->ebit == 0)
  {
    po->ebit = 1;
    WALK_LIST(oa, po->area_list)
    {
      schedule_rt_lsa(oa);
    }
  }
}

void
flush_ext_lsa(net *n, struct proto_ospf *po)
{
  u32 rid = po->proto.cf->global->router_id;
  struct ospf_area *oa;
  struct top_hash_entry *en;

  /* FIXME proper handling of LSA IDs and check for the same network */
  u32 lsaid = ipa_to_lsaid(n->n.prefix);

  if (en = ospf_hash_find(po->gr, 0, lsaid, rid, LSA_T_EXT))
    {
      /* FIXME this is nonsense */
      WALK_LIST(oa, po->area_list)
	{
	  ospf_lsupd_flush_nlsa(po, en);
	}
    }
}


#ifdef OSPFv3

static void *
originate_link_lsa_body(struct ospf_iface *ifa, u16 *length)
{
  struct proto_ospf *po = ifa->oa->po;
  struct ospf_lsa_link *ll;
  int i = 0;
  u8 flags;

  ASSERT(po->lsab_used == 0);
  ll = lsab_allocz(po, sizeof(struct ospf_lsa_link));
  ll->options = ifa->oa->options | (ifa->priority << 24);
  ll->lladdr = ifa->lladdr;
  ll = NULL; /* buffer might be reallocated later */

  struct ifa *a;
  WALK_LIST(a, ifa->iface->addrs)
    {
      if ((a->flags & IA_SECONDARY) ||
	  (a->scope < SCOPE_SITE))
	continue;

      flags = (a->pxlen < MAX_PREFIX_LENGTH) ? 0 : OPT_PX_LA;
      put_ipv6_prefix(lsab_alloc(po, IPV6_PREFIX_SPACE(a->pxlen)),
		      a->ip, a->pxlen, flags, 0);
      i++;
    }

  ll = po->lsab;
  ll->pxcount = i;
  *length = po->lsab_used + sizeof(struct ospf_lsa_header);
  return lsab_flush(po);
}

void
originate_link_lsa(struct ospf_iface *ifa)
{
  struct ospf_lsa_header lsa;
  struct proto_ospf *po = ifa->oa->po;
  struct proto *p = &po->proto;
  u32 rid = po->proto.cf->global->router_id;
  void *body;

  /* FIXME check for vlink and skip that? */
  OSPF_TRACE(D_EVENTS, "Originating Link_lsa for iface %s.", ifa->iface->name);

  lsa.age = 0;
  lsa.type = LSA_T_LINK;
  lsa.id = ifa->iface->index;
  lsa.rt = rid;
  lsa.sn = ifa->link_lsa ? (ifa->link_lsa->lsa.sn + 1) : LSA_INITSEQNO;
  u32 dom = ifa->iface->index;

  body = originate_link_lsa_body(ifa, &lsa.length);
  lsasum_calculate(&lsa, body);
  ifa->link_lsa = lsa_install_new(po, &lsa, dom, body);
  ospf_lsupd_flood(po, NULL, NULL, &lsa, dom, 1);
}

void
update_link_lsa(struct ospf_iface *ifa)
{
  if (ifa->link_lsa && ((ifa->link_lsa->inst_t + MINLSINTERVAL) > now))
    return;
  /*
   * It's too early to originate new link LSA. We will
   * try to do it next tick
   */
  originate_link_lsa(ifa);
  ifa->origlink = 0;
}

static void *
originate_prefix_rt_lsa_body(struct ospf_area *oa, u16 *length)
{
  struct proto_ospf *po = oa->po;
  struct ospf_iface *ifa;
  struct ospf_lsa_prefix *lp;
  u32 rid = po->proto.cf->global->router_id;
  int net_lsa;
  int i = 0;
  u8 flags;

  ASSERT(po->lsab_used == 0);
  lp = lsab_allocz(po, sizeof(struct ospf_lsa_prefix));
  lp->ref_type = LSA_T_RT;
  lp->ref_id = 0;
  lp->ref_rt = rid;
  lp = NULL; /* buffer might be reallocated later */

  WALK_LIST(ifa, po->iface_list)
  {
    if ((ifa->oa != oa) || (ifa->state == OSPF_IS_DOWN))
      continue;

    if ((ifa->type == OSPF_IT_BCAST) ||
	(ifa->type == OSPF_IT_NBMA))
      net_lsa = bcast_net_active(ifa);
    else
      net_lsa = 0;

    struct ifa *a;
    WALK_LIST(a, ifa->iface->addrs)
      {
	if (((a->pxlen < MAX_PREFIX_LENGTH) && net_lsa) ||
	    (a->flags & IA_SECONDARY) ||
	    (a->flags & IA_UNNUMBERED) ||
	    configured_stubnet(oa, a))
	  continue;

	flags = (a->pxlen < MAX_PREFIX_LENGTH) ? 0 : OPT_PX_LA;
	put_ipv6_prefix(lsab_alloc(po, IPV6_PREFIX_SPACE(a->pxlen)),
			a->ip, a->pxlen, flags, ifa->cost);
	i++;
      }
  }

  /* FIXME Handle vlinks? see RFC5340, page 38 */

  struct ospf_stubnet_config *sn;
  WALK_LIST(sn, oa->ac->stubnet_list)
    if (!sn->hidden)
      {
	flags = (sn->px.len < MAX_PREFIX_LENGTH) ? 0 : OPT_PX_LA;
	put_ipv6_prefix(lsab_alloc(po, IPV6_PREFIX_SPACE(sn->px.len)),
			sn->px.addr, sn->px.len, flags, sn->cost);
	i++;
      }

  lp = po->lsab;
  lp->pxcount = i;
  *length = po->lsab_used + sizeof(struct ospf_lsa_header);
  return lsab_flush(po);
}

void
originate_prefix_rt_lsa(struct ospf_area *oa)
{
  struct ospf_lsa_header lsa;
  struct proto_ospf *po = oa->po;
  u32 rid = po->proto.cf->global->router_id;
  void *body;

  lsa.age = 0;
  lsa.type = LSA_T_PREFIX;
  lsa.id = 1 << 31;
  lsa.rt = rid;
  lsa.sn = oa->pxr_lsa ? (oa->pxr_lsa->lsa.sn + 1) : LSA_INITSEQNO;
  u32 dom = oa->areaid;

  body = originate_prefix_rt_lsa_body(oa, &lsa.length);
  lsasum_calculate(&lsa, body);
  oa->pxr_lsa = lsa_install_new(po, &lsa, dom, body);
  ospf_lsupd_flood(po, NULL, NULL, &lsa, dom, 1);
}


static inline int
prefix_space(u32 *buf)
{
  int pxl = *buf >> 24;
  return IPV6_PREFIX_SPACE(pxl);
}

static inline int
prefix_same(u32 *b1, u32 *b2)
{
  int pxl1 = *b1 >> 24;
  int pxl2 = *b2 >> 24;
  int pxs, i;
  
  if (pxl1 != pxl2)
    return 0;

  pxs = IPV6_PREFIX_WORDS(pxl1);
  for (i = 1; i < pxs; i++)
    if (b1[i] != b2[i])
      return 0;

  return 1;
}

static inline u32 *
prefix_advance(u32 *buf)
{
  return buf + prefix_space(buf);
}

static void
add_prefix(struct proto_ospf *po, u32 *px, u32 *pxl, int *pxc)
{
  int i;
  for (i = 0; i < *pxc; i++)
    {
      if (prefix_same(px, pxl))
	{
	  /* Options should be logically OR'ed together */
	  *pxl |= *px;
	  return;
	}
      pxl = prefix_advance(pxl);
    }

  ASSERT(pxl == lsab_end(po));

  int pxspace = prefix_space(px);
  pxl = lsab_alloc(po, pxspace);
  memcpy(pxl, px, pxspace);
  (*pxc)++;
}


static void *
originate_prefix_net_lsa_body(struct ospf_iface *ifa, u16 *length)
{
  struct proto_ospf *po = ifa->oa->po;
  struct ospf_lsa_prefix *lp;
  struct ospf_lsa_link *ll;
  struct ospf_neighbor *n;
  struct top_hash_entry *en;
  u32 rid = po->proto.cf->global->router_id;
  u32 *pxb;
  int i, j, offset;


  ASSERT(po->lsab_used == 0);
  lp = lsab_allocz(po, sizeof(struct ospf_lsa_prefix));
  lp->ref_type = LSA_T_NET;
  lp->ref_id = ifa->net_lsa->lsa.id;
  lp->ref_rt = rid;
  lp = NULL; /* buffer might be reallocated later */

  i = 0;
  offset = po->lsab_used;

  /* Find all Link LSA associated with the link and merge their prefixes */
  WALK_LIST(n, ifa->neigh_list)
    if ((n->state == NEIGHBOR_FULL) &&
      	(en = ospf_hash_find(po->gr, ifa->iface->index, n->iface_id, n->rid, LSA_T_LINK)))
      {
	ll = en->lsa_body;
	pxb = ll->rest;

	for (j = 0; j < ll->pxcount; j++)
	  {
	    add_prefix(po, pxb, lsab_offset(po, offset), &i);
	    pxb = prefix_advance(pxb);
	  }
      }

  lp = po->lsab;
  lp->pxcount = i;
  *length = po->lsab_used + sizeof(struct ospf_lsa_header);
  return lsab_flush(po);
}

void
originate_prefix_net_lsa(struct ospf_iface *ifa)
{
  struct ospf_lsa_header lsa;
  struct proto_ospf *po = ifa->oa->po;
  u32 rid = po->proto.cf->global->router_id;
  void *body;

  lsa.age = 0;
  lsa.type = LSA_T_PREFIX;
  lsa.id = ifa->iface->index;
  lsa.rt = rid;
  lsa.sn = ifa->pxn_lsa ? (ifa->pxn_lsa->lsa.sn + 1) : LSA_INITSEQNO;
  u32 dom = ifa->oa->areaid;

  body = originate_prefix_net_lsa_body(ifa, &lsa.length);
  lsasum_calculate(&lsa, body);
  ifa->pxn_lsa = lsa_install_new(po, &lsa, dom, body);
  ospf_lsupd_flood(po, NULL, NULL, &lsa, dom, 1);
}

void
flush_prefix_net_lsa(struct ospf_iface *ifa)
{
  struct proto_ospf *po = ifa->oa->po;
  struct proto *p = &po->proto;
  struct top_hash_entry *en = ifa->pxn_lsa;
  u32 dom = ifa->oa->areaid;

  if (en == NULL)
    return;

  OSPF_TRACE(D_EVENTS, "Flushing Net Prefix lsa for iface \"%s\".",
	     ifa->iface->name);
  en->lsa.sn += 1;
  en->lsa.age = LSA_MAXAGE;
  lsasum_calculate(&en->lsa, en->lsa_body);
  ospf_lsupd_flood(po, NULL, NULL, &en->lsa, dom, 0);
  flush_lsa(en, po);
  ifa->pxn_lsa = NULL;
}


#endif


static void
ospf_top_ht_alloc(struct top_graph *f)
{
  f->hash_size = 1 << f->hash_order;
  f->hash_mask = f->hash_size - 1;
  if (f->hash_order > HASH_HI_MAX - HASH_HI_STEP)
    f->hash_entries_max = ~0;
  else
    f->hash_entries_max = f->hash_size HASH_HI_MARK;
  if (f->hash_order < HASH_LO_MIN + HASH_LO_STEP)
    f->hash_entries_min = 0;
  else
    f->hash_entries_min = f->hash_size HASH_LO_MARK;
  DBG("Allocating OSPF hash of order %d: %d hash_entries, %d low, %d high\n",
      f->hash_order, f->hash_size, f->hash_entries_min, f->hash_entries_max);
  f->hash_table =
    mb_alloc(f->pool, f->hash_size * sizeof(struct top_hash_entry *));
  bzero(f->hash_table, f->hash_size * sizeof(struct top_hash_entry *));
}

static inline void
ospf_top_ht_free(struct top_hash_entry **h)
{
  mb_free(h);
}

static inline u32
ospf_top_hash_u32(u32 a)
{
  /* Shamelessly stolen from IP address hashing in ipv4.h */
  a ^= a >> 16;
  a ^= a << 10;
  return a;
}

static inline unsigned
ospf_top_hash(struct top_graph *f, u32 domain, u32 lsaid, u32 rtrid, u32 type)
{
  /* In OSPFv2, we don't know Router ID when looking for network lsas.
     dirty patch to make rt table calculation work. */

  return (ospf_top_hash_u32(lsaid) + type +
#ifdef OSPFv2
	  ((type == LSA_T_NET) ? 0 : ospf_top_hash_u32(rtrid)) +
#else /* OSPFv3 */
	  ospf_top_hash_u32(rtrid) +
#endif
	  domain) & f->hash_mask;

  /*
  return (ospf_top_hash_u32(lsaid) + ospf_top_hash_u32(rtrid) +
	  type + areaid) & f->hash_mask;
  */
}

/**
 * ospf_top_new - allocated new topology database
 * @p: current instance of ospf
 *
 * this dynamically hashed structure is often used for keeping lsas. mainly
 * its used in @ospf_area structure.
 */
struct top_graph *
ospf_top_new(pool *pool)
{
  struct top_graph *f;

  f = mb_allocz(pool, sizeof(struct top_graph));
  f->pool = pool;
  f->hash_slab = sl_new(f->pool, sizeof(struct top_hash_entry));
  f->hash_order = HASH_DEF_ORDER;
  ospf_top_ht_alloc(f);
  f->hash_entries = 0;
  f->hash_entries_min = 0;
  return f;
}

void
ospf_top_free(struct top_graph *f)
{
  rfree(f->hash_slab);
  ospf_top_ht_free(f->hash_table);
  mb_free(f);
}

static void
ospf_top_rehash(struct top_graph *f, int step)
{
  unsigned int oldn, oldh;
  struct top_hash_entry **n, **oldt, **newt, *e, *x;

  oldn = f->hash_size;
  oldt = f->hash_table;
  DBG("re-hashing topology hash from order %d to %d\n", f->hash_order,
      f->hash_order + step);
  f->hash_order += step;
  ospf_top_ht_alloc(f);
  newt = f->hash_table;

  for (oldh = 0; oldh < oldn; oldh++)
  {
    e = oldt[oldh];
    while (e)
    {
      x = e->next;
      n = newt + ospf_top_hash(f, e->domain, e->lsa.id, e->lsa.rt, e->lsa.type);
      e->next = *n;
      *n = e;
      e = x;
    }
  }
  ospf_top_ht_free(oldt);
}

#ifdef OSPFv2

u32
ospf_lsa_domain(u32 type, struct ospf_iface *ifa)
{
  return (type == LSA_T_EXT) ? 0 : ifa->oa->areaid;
}

#else /* OSPFv3 */

u32
ospf_lsa_domain(u32 type, struct ospf_iface *ifa)
{
  switch (type & LSA_SCOPE_MASK)
    {
    case LSA_SCOPE_LINK:
      return ifa->iface->index;

    case LSA_SCOPE_AREA:
      return ifa->oa->areaid;

    case LSA_SCOPE_AS:
    default:
      return 0;
    }
}

#endif

struct top_hash_entry *
ospf_hash_find_header(struct top_graph *f, u32 domain, struct ospf_lsa_header *h)
{
  return ospf_hash_find(f, domain, h->id, h->rt, h->type);
}

struct top_hash_entry *
ospf_hash_get_header(struct top_graph *f, u32 domain, struct ospf_lsa_header *h)
{
  return ospf_hash_get(f, domain, h->id, h->rt, h->type);
}

struct top_hash_entry *
ospf_hash_find(struct top_graph *f, u32 domain, u32 lsa, u32 rtr, u32 type)
{
  struct top_hash_entry *e;

  e = f->hash_table[ospf_top_hash(f, domain, lsa, rtr, type)];

#ifdef OSPFv2
  /* dirty patch to make rt table calculation work. */
  if (type == LSA_T_NET)
  {
    while (e && (e->lsa.id != lsa || e->lsa.type != LSA_T_NET || e->domain != domain))
      e = e->next;

    return e;
  }

#endif

  while (e && (e->lsa.id != lsa || e->lsa.type != type || e->lsa.rt != rtr || e->domain != domain))
    e = e->next;

  return e;
}

struct top_hash_entry *
ospf_hash_get(struct top_graph *f, u32 domain, u32 lsa, u32 rtr, u32 type)
{
  struct top_hash_entry **ee;
  struct top_hash_entry *e;

  ee = f->hash_table + ospf_top_hash(f, domain, lsa, rtr, type);
  e = *ee;

  while (e && (e->lsa.id != lsa || e->lsa.rt != rtr || e->lsa.type != type || e->domain != domain))
    e = e->next;

  if (e)
    return e;

  e = sl_alloc(f->hash_slab);
  e->color = OUTSPF;
  e->dist = LSINFINITY;
  e->nhi = NULL;
  e->nh = IPA_NONE;
  e->lb = IPA_NONE;
  e->lsa.id = lsa;
  e->lsa.rt = rtr;
  e->lsa.type = type;
  e->lsa_body = NULL;
  e->nhi = NULL;
  e->domain = domain;
  e->next = *ee;
  *ee = e;
  if (f->hash_entries++ > f->hash_entries_max)
    ospf_top_rehash(f, HASH_HI_STEP);
  return e;
}

void
ospf_hash_delete(struct top_graph *f, struct top_hash_entry *e)
{
  struct top_hash_entry **ee = f->hash_table + 
    ospf_top_hash(f, e->domain, e->lsa.id, e->lsa.rt, e->lsa.type);

  while (*ee)
  {
    if (*ee == e)
    {
      *ee = e->next;
      sl_free(f->hash_slab, e);
      if (f->hash_entries-- < f->hash_entries_min)
	ospf_top_rehash(f, -HASH_LO_STEP);
      return;
    }
    ee = &((*ee)->next);
  }
  bug("ospf_hash_delete() called for invalid node");
}

static void
ospf_dump_lsa(struct top_hash_entry *he, struct proto *p)
{
  /*
  struct ospf_lsa_rt *rt = NULL;
  struct ospf_lsa_rt_link *rr = NULL;
  struct ospf_lsa_net *ln = NULL;
  u32 *rts = NULL;
  u32 i, max;

  OSPF_TRACE(D_EVENTS, "- %1x %-1R %-1R %4u 0x%08x 0x%04x %-1R",
	     he->lsa.type, he->lsa.id, he->lsa.rt, he->lsa.age, he->lsa.sn,
	     he->lsa.checksum, he->domain);


  switch (he->lsa.type)
    {
    case LSA_T_RT:
      rt = he->lsa_body;
      rr = (struct ospf_lsa_rt_link *) (rt + 1);

      for (i = 0; i < lsa_rt_items(&he->lsa); i++)
        OSPF_TRACE(D_EVENTS, "  - %1x %-1R %-1R %5u",
		   rr[i].type, rr[i].id, rr[i].data, rr[i].metric);
      break;

    case LSA_T_NET:
      ln = he->lsa_body;
      rts = (u32 *) (ln + 1);

      for (i = 0; i < lsa_net_items(&he->lsa); i++)
        OSPF_TRACE(D_EVENTS, "  - %-1R", rts[i]);
      break;

    default:
      break;
    }
  */
}

void
ospf_top_dump(struct top_graph *f, struct proto *p)
{
  unsigned int i;
  OSPF_TRACE(D_EVENTS, "Hash entries: %d", f->hash_entries);

  for (i = 0; i < f->hash_size; i++)
  {
    struct top_hash_entry *e;
    for (e = f->hash_table[i]; e != NULL; e = e->next)
      ospf_dump_lsa(e, p);
  }
}

/* This is very inefficient, please don't call it often */

/* I should also test for every LSA if it's in some link state
 * retransmission list for every neighbor. I will not test it.
 * It could happen that I'll receive some strange ls ack's.
 */

int
can_flush_lsa(struct proto_ospf *po)
{
  struct ospf_iface *ifa;
  struct ospf_neighbor *n;

  WALK_LIST(ifa, po->iface_list)
  {
    WALK_LIST(n, ifa->neigh_list)
    {
      if ((n->state == NEIGHBOR_EXCHANGE) || (n->state == NEIGHBOR_LOADING))
        return 0;

      break;
    }
  }

  return 1;
}